Mechanical Model WorkshopShow examples of Timberkits models on the video (www.timberkits.co.uk/educa-tion) and ask them to describe how they think they work in their own words. Ask them to describe the nature of the movements, are they jerky, smooth, fast or slow.

Basic principles and terminology.What is the difference between cogs, cams and wheels?Cogs and gears have teeth to mesh with each other. Cams go round and round and up and down and side to side and can be many different shapes depending on the movement needed. Wheels simply go round and round.

Worksheets and photographs © copyright 2011, all rights reserved

Teacher Worksheet

For the purposes of these kits the students need to be familiar with the following;

Drive shaft

Cam follower

Friction wheel

Crank handle

Cog/Gear

Wheel

TriangularCam

CircularCam

Having discussed these mechanical elements, can they identify them on themodels in the video? Remember! Cams come in many different shapes.

Construction.

To make their own models each student will need to think of an object and anaction and then choose the appropriate mechanisms to make it work.

While they are thinking of this it is a good idea to glue the bench, crank handle and drive shaft together so it will be firm and dry when they start working on it.

Crank handle glued to drive shaft

Bench assembled and glued

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Follows the movement ofthe cam.

Is driven by another wheel or cam by friction alone.

Mechanical Model WorkshopPlenty of time and thought needs to be given to the sketching of design but some students will work best be getting stuck into the practicalities straight away,looking at materials, experimenting with mechanical components etc. It doesn’t matter which way they go about it so long as they can show they have done some

Worksheets and photographs © copyright 2011, all rights reservedPage 2 of 3

Suggestions for modelling materials.

Wrapping paper, tissue, card, fabric, bamboo, wood, plastic, wire, string, blue tack, plasticine, ping pong balls, drinking straws etc.

Other helpful hints.

Some objects will move better with weight, other will need to be light. Plasticine and blue tack are useful for adding weight if needed.Some objects will need careful balancing, e.g. If they tend to tip to one side there mechanism may ‘bind’.Models can be painted or coloured but make sure no paint gets on to working parts or surfaces. Sometimes bits may need sanding or waxing to help them move smoothly. Sometimes bits will need more friction by roughing up the surface with something sharp.Bamboo can be cut by scoring round with scissors then snapping.

An example of a commercially produced model using the same mechanisms found in the students kits

thorough thinking before embarking on the real model.

Some may find it easiest to simply start withcardboard cutouts.

Encourage the children to try their model without glue before permanently fixing, and refer toinstruction tips on the video.

Mechanical Model WorkshopEncourage the children to use one and no more than two different mechanisms. See below illustrations of possible arrangements. These can be seen in operation on the video.

Worksheets and photographs © copyright 2011, all rights reservedPage 3 of 3

The spider has a jerky, up and down movement on a triangle cam. The wheel stuck on the bottom of the cam follower allows it ride smoothly over the points of the triangle.

The two round cams glued in opposition to each other make the wheel on the cam follower go from side to side. The additional peg prevents it from going all the way round.

Here there are two side to side mechanisms making the toad’s eyes swivel.

A friction wheel on the end of the cam follower is driven by anordinary wheel on the drive shaft which turns the Peacock round and round showing off his beautiful tail feathers

One cam lifts the helicopter, the other cam both lifts and spins the blades. The cam follower carrying the blades is not stuck to the body of the helicopter.